Reference

Reading a floor plan

A floor plan is not a list of rooms. It is a drawing of how people move through a building, and of where the daylight falls.

Start with the circulation

Trace the route from the front door to each room, then from the kitchen to wherever food is eaten, then from every bedroom to a bathroom. Those three routes determine how a house feels to live in far more than the size of any individual room.

Plans where every room opens off a hall behave differently from plans where rooms open off each other. Neither is better; they suit different households. But a room that can only be reached by crossing another room is a genuinely different proposition from one that cannot, and a plan makes that visible in a way photographs never do.

Find north

If the plan carries an orientation marker, it answers a question no photograph will: which rooms get morning light and which get evening light, and whether the garden is in sun when the household is likely to use it. If there is no marker, the position of the property on its street usually allows a reasonable guess.

Check the scale, then check it again

Plans are drawn to fit a page, so two plans printed at the same size may be at quite different scales. Any dimensions given are the reliable part; the apparent size of a room on paper is not.

It is worth measuring a room in a home you already know and holding that figure in mind. Most people can judge whether a stated dimension is generous or tight far better than they can judge a rectangle on a page.

Read the walls

Thick walls usually carry load; thin ones usually do not. That distinction governs what can be changed cheaply and what cannot. A plan will not tell you definitively, but a wall that lines up with a wall on the floor above, or that runs the depth of the building, is more likely to be structural.

Look also for chimney breasts, which appear as projections in a room, and for where the drainage must run, which is usually indicated by the position of bathrooms and kitchens stacked above one another.

Spot the extension

Extensions announce themselves on plans: a change in wall thickness, a room with a different geometry, a window in an internal wall, a step in the roof line, or a bathroom in an odd position. None of that is a problem in itself. It is a prompt to ask when the work was done and whether the paperwork for it exists.

What plans leave out

Plans do not show ceiling heights, floor levels, the condition of anything, the direction a door swings, where radiators and sockets are, or how much of a room is usable once the door and the circulation route are accounted for. A large room with four doors can hold less furniture than a smaller room with one.